Stack gas smoke control apparatus



p 1940- M. MATANOVlCH-MANOV ET AL 2,215,707

STACK GAS SMOKE CONTROL APPARATUS Filed Sept. 19, 1958 2 Sheets-Sheet l BY 5 W ATTORNEY p 1940- M. MATAN0VlCH-MANOV ET AL 2,215,707

$TACK GAS SMOKE CONTROL APPARATUS Filed Sept 19, 1958 2 Sheets-Sheet 2 V 5 WW Y mMw w "n h/gm mmfi w r f aflm/ My Temp "E Patented Sept. 24, 1940 ENT OFFICE STACK GAS SMOKE CONTROL AFPABATUS Mateo Matanovich-Manov, Berkeley, and Arthur .8. Holmes, Oakland, Calif.

Application September19, 1938, Serial No. 230,594

3 Claims. (01. 261-18) The invention relates to apparatus for treating and cleansing of stack gases for removal of smoke,

dust and odoriferous components and the like.

An object of the present invention is to provide an apparatus of the character described which is designed and arranged to handle a large volume of stack gas ranging in the order of thousands of cubic feet per minute, and which will produce a substantially complete elimination from such gas of all smoke, dust, odoriferous components and other foreign matter, whereby the resultant cleansed stack gas maybe discharged to the atmosphere in a clean, cool state, enabling a harmless, invisible diffusion of such gases in the atmosphere.

Another object of the invention is to provide an apparatus of the above character which will provide an efficient and sanitary disposal of the various components removed from the stack gases.

A further object of the invention is to provide an apparatus of the character described which is particularly adaptable to garbage incinerators and will handle with maximum efliciency and flexibility varying quantities and quality of gases and smoke produced by seasonal changes in the quality of the garbage as to combustible components and moisture content, etc.

Yet another object of the invention is to provide an apparatus of the character above which is designed for substantially continuous operation and wherein various portions of the load may be temporarily shifted to diiierent units of the device to take out of operation other units for inspection and repair, whereby plant shut-down may be substantially totally avoided.

The invention possesses other objects and features of advantage, some of which, with the foregoing, Will be set forth in the following description of the preferred form of the invention which is illustrated in the drawings accompanying and forming part of the specification. It is to be.

understood, however, that variations in the showing made by the said drawings and description may be adopted within the scope of the invention as set forth in the claims.

Referring to said drawings:

Figure 1 is a side elevation of a stack gas smoke control apparatusconstructed in accordance with the present invention, a portion of the apparatus being broken awayand shown in section.

Figure 2 is a plan sectional view of a portion of the apparatus at the discharge end thereof and is taken substantially on the plane of line 2-2 of Figure 1.

Figure 3 is a vertical cross-sectional view of certain longitudinal scrubber tubes used in the present invention.

Figure 4 is a view similar to Figure 3 but is taken at a different longitudinal position.

Figure 5 is a graphic representation of the tem- 5 perature reduction of the stack gases as the same passes through different portions of the apparatus.

The smoke control apparatus of the present inventionand as illustrated in the accompanying drawings, consistsbriefly of a plurality of gas conduits or scrubber tubes ll, I2 and 13 which are connected to a stack of a furnace or incinerator (not shown). These'tubes are of substantial diameter and length and are equipped along their length at longitudinally spaced positions with a plurality of water spray units i l for washing and cooling of the stack gases passed through the tubes, and the removal of dust and smoke and condensable and soluble components in the stack gases. The Water sprayed into the interior of the scrubber tubes is removed from the tubes together with the matter washed out of the gases by the water, by means of a plurality of longitudinally spaced drains It. The gas is discharged from ends ll, [8 and i9 of the tubes into a filter chamber 2i and is drawn through such chamber by means of a suction fan 22 and finally discharged into a short, vertical stack 23 providing a chlorine diffusing chamber. The principal function of the water spray units is to provide a thor-v ough washing and cleansing of the stack gases and to cause a sufficient cooling of such gases to con dense out the water vapor and other condensable components contained in the stack gases, so that the volume of gas discharged from the tubes is greatly reduced from that which enters: the tubes.

The number and diameter and length of the scrubber tubes depends in each instance upon the amount and quality of stack gas to be handled. 40 In each case, however, and as an essentially new function of the presentapparatus, the stack gases in addition to being thoroughly cleansed, are cooled to a temperature not substantially greater than atmospheric so as to first provide a substantially complete elimination of the liquid component of the gases and secondly, to provide a discharge of the gases to the atmosphere without any visible clouding of the atmosphere into which the gases are discharged. The present apparatus has been designed to receive stack gases at temperatures ranging between 500 F. and 1000 F. and to discharge such gases'to the atmosphere at between Rand F. Further, the apparatus as herein disclosed is designed to handle 55 large volumes of stack gas such as obtained from a garbage incinerator disposing of the garbage of an entire community. The present apparatus is designed to receive stack gases in the order of twenty-five to thirty thousand cubic feet per minute and with an average run of garbage will reduce this input volume to about ten thousand to eleven thousand cubic feet per minute at the discharge end of the scrubber tubes, or a reduction of approximately sixty percent.

The gases are removed from a conventional type of stack or the discharge end of a furnace by means of a manifold conduit 24 and the latter is preferably formed with a substantially horizontal section 26 connected to the furnace or stack and a substantially vertical input conduit section 21, which is arranged for connection to the bank of scrubber tubes I I, I2 and IS. The latter are preferably arranged in substantially horizontal position and may be mounted as here shown in a Vertical bank and connected at their input ends 28, 29 and 3! to the vertical conduit manifold section 21'. Preferably, the base of the section 21 is provided with a removable closure member 32 covering an opening to the interior of the section for permitting withdrawal from the section of dust, soot or other material deposited therein.

Preferably, the inlet ends 28, 29 and 3! of the scrubber tubes are provided with a suitable damper 33, 34 and 36 for regulating the stack gas flow into each of the scrubber tubes. In this manner any one or two of the scrubber tubes may be closed off and the entire load diverted through the scrubber tube remaining open, and the scrubber tube so closed may be made thus available for inspection, cleaning out and repair. In this manner the plurality arrangement of scrubber tubes lends substantial flexibility to the device in handling various outputs of stack gases and also in enabling the working on any of the scrubber tubes without shutting down of the plant.

As an important feature of the present invention the amount and distribution of water sprayed into the scrubber tubes is so controlled in relation to the volume and character and temperature of the stack gases as to cause a substantially complete vaporization of the water sprayed into the scrubber tubes over an initial length of the tubes and dehumidification of the stack gases over the remainder of the length of the scrubber tubes. This arrangement has been carefully worked out so as to avoid such a volumetric increase in the gas flow in the aforesaid initial portion of the scrubber tubes, and yet by operating with a substantially maximum volumetric increase a large amount of spray water may be used for cooling of the gases. Thus the operation of the scrubber tubes over the initial length of the scrubber tubes is to cause a substantially uniform spraying of the hot stack gases and generation of water vapor which mixes with the stack gases to increase the volumetric flow. While the volume of gas is increased by the water vapor, the stack gas itself is cooled by the water thus evaporated and the over-all temperature of the gas reduced, causing a corresponding reduction in volume tending to offset in part the volume increase due to the water vapor. As further water is sprayed into the gas the temperature of the gas is reduced by steps to the boiling point of the water, when upon further cooling the water sprayed into the gas and the condensable components of the gas start to condense out. This condensing operation takes place in the second section of the scrubber tubes and the gas which is finally discharged contains only as much water vapor as can be held in a relatively cool gas of F. to F.

The approximate temperature reduction of the stack gas is shown by the curve illustrated in Figure 5 of the drawings. It will be noted from the curve that the stack gas temperature reduces in the initial stages along a curved line to approximately the boiling point of water and reduces after this point along a substantially lineal path. The first portion of the curve is indicated in the drawing as a vapor stage and the second portion of the curve is indicated as a dehumidification stage.

To produce the above result, various sizes and proportions of the apparatus may be used depending upon the quantity and quality of the stack gases. For example, when the device is used in conjunction with a garbage incinerator as aforementioned, supplying between twentyfive thousand and thirty thousand cubic feet of gas per minute at a temperature between 500 F. and 1000 F., We prefer to use a bank of three scrubber tubes, each having a diameter of approximately four feet and a length of approximately seventy-eight feet. In this design, a total of twelve banks of spray units are mounted in substantially equally longitudinally spaced positions in the tubes with approximately five feet, seven inches between each of the banks, and water is sprayed from each of the banks at the rate of approximately fourteen to eighteen gallons per minute. In this manner the gas is treated with water in the proportion of approximately fifty cubic feet of gas to one gallon of water.

The construction and arrangement of the spray units forms an important feature of the present arrangement and as here shown, each bank is composed of four sprayer heads or nozzles 31, which are positioned in circumferentially spaced relation within the scrubber tubes and are approximately equally spaced from each other and are preferably positioned at a substantially constant distance from the axis of the scrubber tube. Preferably, however, while on a constant radius the nozzles are closer to the wall of the scrubber tube than to the axis of the tube and each of the nozzles are arranged to spray a conical spray of Water having an axis generally parallel to the axis of the tube and of such transverse dimension as to reach to the center axis of the tube. In this manner two important results are produced. First, the density of the water spray increases towards the axis where the gaseous fiow is the greatest and secondly, a substantial amount of water is deflected off the side wall of the scrubber tube, which affords a secondary increase of condensation by the reflection of the condensed water particles from the wall of the scrubber tube. Preferably, the movement of the water spray is longitudinal in the direction of gaseous flow in the scrubber tubes to assist the general longitudinal flow of the gas, but in some instances, particularly where shorter lengths of scrubber tubes are used, the direction of movement of the water spray may be reversed so as to oppose the gaseous flow.

Preferably and as above noted, we use a plurality of longitudinally spaced drains 16 for removing from the scrubber tubes any water and condensate present almost as soon as the same forms or deposits at the bottom of the tube. Preferably, the drains [6 are mounted adjacent to each of the spray banks so that the water sprayed fromone bank may be'drained from the next forward drain. In this manner any corrosive liquids which may be formed bythe washing of the stack gases are quickly removed and the possibility of corrosive damage to..the scrubber tubes is minimized. Also, .the relatively large quantity of water used in the present process is sufficient to cause a substantial dilution of corrosive liquids, so that their deleterious effect is relatively small. Preferably, the drains are connected by pipes 38 and the liquid removed carried directly to a sewer 39. If desired, the drain pipes 38 may be connected to a filter box 4| containing sand or the like for filtering of the liquid prior to discharge into the sewer or in instances where water is relatively expensive, the water may be filtered by such a sand box or the like and re-circulated through the apparatus.

The discharge ends I1, I8 and I9 of the scrubber tubes are connected in the present construction to a relatively short, vertical inlet tower 42 containing a plurality of baffles 43 for retarding the gas fiow and effecting a further removal of suspended matter. From the inlet tower 42 the gas is passed into the filter chamber 2! which is formed in a housing or casing 44. The chamber 2| is preferably enlarged in cross-sectional area over that of the combined area of the scrubber tubes, so that the gas flow is further retarded when passed through a filter 46 positioned in the chamber. This filter may be of substantially any desired construction and as here shown, is in the form of a roller type metallic air filtering screen 41, which is submerged at its lower end in an oil bath 48. A second dry metallic filter 49 of a roller type is preferably mounted behind the filter 41 for further screening and filtering of the gas discharged. The gas is drawn from the filter chamber, as aforementioned, by means of a suction fan 22 which discharges the gas into the vertical chlorinating stack 23. The positioning of the suction fan at thislocation in the apparatus is of considerable importance, since it permits of the use of a relatively inexpensive fan which need not withstand high combustion temperatures as is usual in the case of a force-draft furnace fan, and also at this position of the apparatus the quantity of gas is very greatly reduced, so that the fan need not handle all of the stack gases. Mounted in the base of the stack 23 is a spray head 5| which is adapted for connection to a suitable source of chlorinating gas for spraying the emerging stack gases with chlorine and causing the chlorine and stack gases to mix while rising through the chamber '23 prior to discharge to the atmosphere. The use of chlorine in this manner will remove any remaining trace of odor in the gas.

Preferably, a series of Pitot tubes 52 are mounted in the scrubber tubes for indicating the quantitative gas flow in the tubes to facilitate proper regulation of the water and gas flow.

The use of a plurality of scrubber tubes, as herein noted, provides in addition to the advantages indicated above, various other important advantages over a single scrubber tube of equivalent cross-sectional area. Some of these advantages are an increased over-all heat transfer coefiicient of the apparatus; the prevention of chaneling of the gases; the reduction in quantity of scrubbing water required; an increased scrubbing efficiency caused by an increased wetted perimeter and surface of the scrubber tubes, thus increasing the action of condensation and collection of smoke particles without altering the gas velocity; the obtaining of a secondaryincrease in condensation surface by refiection ofcondensed water'particles from the Walls of the scrubbers; the handling with maximum efficiency. and flexibility varying quantity and quality of smoke; diminishing the vertical and horizontal distance through which the smoke particles must travel before being removed from the scrubber tubes, thus preventing the re-suspension of previously scrubbed smoke particles by diminishing the time of residence of these particles in the turbulent gas zone within the scrubber units; and the avoiding of plant shut-downs by enabling one or more scrubbers to be temporarily disconnected for cleaning out and repair while the total load is shifted to the remaining scrubbers. Where the load is so shifted, it is desirable to increase the water sprayed into the scrubber tubes in operation by increasing the water pressure applied to the sprayer units.

It will now be clear that the apparatus of the present invention is effective to handle a relatively large volume of stack gas and to effect a complete cleansing of such gas of all smoke, dust, soot and foreign and odoriferous components, and to further remove from such gas a majority of the condensible liquid therein, whereby the resulting gas is clean and cool and greatly reduced in volume, and may be liberated to the atmosphere with which it will invisibly and harmlessly combine.

We claim:

1. A stack gas smoke control apparatus comprising, a manifold conduit adapted for connection to a furnace stack for receipt of stack gases therefrom, a plurality of elongated tubes each connected at one end to said first conduit, a plurality of water spray units mounted in each of said tubes for washing and cooling said gases and liquefying condensable components thereof, a casing connected to the discharge end of each of said tubes and providing an expansion chamber for gases received from said tubes, a filter mounted in said expansion chamber, a stack connected to said casing at the discharge side of said filter, a suction fan mounted in said casing at the discharge side of said filter for drawing gases therethrough and through said tubes for discharge into said stack, and a chlorine gas spray head mounted in the base of said stack for chlorinating said gases prior to discharge thereof to the atmosphere.

2. A stack gas smoke control apparatus comprising, a manifold conduit adapted for connection to a furnace stack for receipt of stack gases therefrom, a system of elongated substantially horizontal tubes connected to said manifold conduit for receipt of said gases, a plurality of water spray units mounted in said elongated tubes for cooling said gases and condensing vapors and removing suspended particles therefrom, a chamber connected to said tubes for receipt of washed gases, an exhaust stack for said chamber, a draft fan for exhausting gases from said chamber to said exhaust stack, and a chlorination unit in said exhaust stack for final treatment of said gases before their communication with the atmosphere.

3. A stack gas smoke control apparatus comprising, an elongated substantially horizontally arranged conduit adapted for connection at one end to a furnace stack for receipt of stack gases therefrom, water spray means mounted in said the discharge end'of said conduit for drawing the gas through said conduit and discharging the same tothe atmosphere.

MATEO MATANOVICH-1VIANOV. ARTHUR S. HOLMES. 

